Analysing an experiment
Shini and Simon talk through the steps that should be taken when analysing a science investigation
Studying the data
Data collected during an investigation is normally displayed in a results table. At this point you can study your repeats to see how close they are. Repeats that are similar are said to be precise. Sometimes you may have an anomalyA result that is unusual or unexpected. repeat. If this is the result of a measurement error it can be ignored, although it is good practice to repeat that measurement again.
Analyse data with Dr Alex Lathbridge
Listen to the full series on ±«Óătv Sounds.
Dr Alex Lathbridge breaks down how to tackle Data Analysis questions.
How to display the data
It can be difficult to see the relationship between the variables from a results table so often the means are plotted on a graph or chart to analyse the results further. It is important to choose the most appropriate type of graph or chart.
If both the independent and dependent variables are continuous variationVariation that shows a wide range of intermediate values between two extremes. They can be measured. data then a line graph (also called a scatter graph) is the best choice. Usually a line of best fit will be drawn to show the trend in the data. This will allow you to see the relationship between the variables, for example if they are proportionalWhen two quantities have the same ratio or relative size. For example, current is proportional to voltage if the current doubles when the voltage is doubled..
Also, you can see if any of the values are anomalous as they will be placed far away from the line of best fit. An example of where a line graph would be used is in an investigation to see if temperature affects the rate of a reaction.
A bar chart is used if the independent variable has different categories. For example, to display the frequency of different eye colours in a group of people.